1. By deault press the winkey once in gnome-shell will call up the main menu, this is not a big problem, but some shortcuts 'winkey + somekey' I set are not functional. For example 'f' and 'space' do not work, however 't' works, weird. To solve it:system settings -> region and language -> layouts -> options -> alt/win key behaior -> meta is mapped to win keys

2. The urllib in python support https links, but it does not validate the certificates (some say that this will be implemented in the future). So I found the m2cypto module, it wraps urllib, and an exception will be thrown when there is problem with the certificate, however it sometimes went stuck when nothing wrong... Later I realized that it would be good just to call 'wget'

3. I cannot find 'Startup Application' in the gnome control center, but I can still run gnome-session-properties

4. maximus: a small tool that eliminate the title bar of maximized windows, looks quite good with gnome-shell.

5. Through the files /usr/share/gnome-shell/js/ui/dateMenu.js & panel.js we can hack the top bar of gnome shell, for example I renamed 'Activities', customized the datetime format, and removed the accessibility icon.